Zooming and scrolling

In the bottom bar, the Preview button (available with most tools) displays the current zoom level.

Clicking on this button opens a menu with a thumbnail of the full picture you're editing, along with zoom level controls.

Moving the view

You may use the thumbnail preview to move the view within a huge image, but it's not the simplest way to do it:

Aside of the scrollbars, using keyboard shortcuts, touch gestures, or sliding with the mouse middle-click, might be more efficient.

Zooming in or out

You can use the thumbnail preview controls to change the zoom level, but you can also use keyboard shortcuts, touch gestures, or you can scroll while pressing the Ctrl key. This behavior can be changed:

Configuration

In the app preferences, you can set how you want to zoom on the image: by default, scrolling on the canvas moves the current view in the direction of the scrolling, and scrolling while holding the Ctrl key zooms in or out. You can turn off the switch to invert these behaviors.

If you rely on an old-school mouse, it's pertinent to turn this setting off: the mouse wheel will then directly zoom in and out. To browse the image, you can move your mouse on the canvas while you hold its middle button: it'll to move the current view in any direction.

If you have a trackpad, or a touchscreen, it's recommended to keep using the Ctrl key to zoom (default behavior): with such a device, you're able to intuitively scroll in both directions to browse the entire image. If your device supports multi-touch gestures, you'll even be able to zoom in and out using the default touch gestures (stretch or pinch with two fingers), which will not work if you turn off this setting.

Of course, it's always possible to control the zoom level with the keyboard shortcuts, or the buttons under the thumbnail preview.